The invention relates to a hot-gas machine, for example, a hot-gas reciprocating engine or a hot-gas turbine, in which a gaseous medium performs a closed thermodynamic cycle. The machine includes a heater in which the cyclic medium receives heat from the outside from a source of heat; particularly a heat accumulator, a heat transfer device is provided between the heat source and the heater, said device containing a heat transporting medium which absorbs heat from the heat source while changing over from the liquid phase to the vapour phase, and giving off heat to the heater while changing-over from the vapour phase into the liquid phase. A machine of this kind is known from Dutch Patent Specification No. 58,355.
The heat transfer device may serve various purposes. It may be advantageous for reasons of space to arrange the heat source at a distance from the heater; for example, in vehicles may be equipped with a thermodynamic engine, in which the heat is furnished by a re-chargeable heat accumulator arranged elsewhere in the vehicle. The nature of the heat source may involve the desirability or necessity to dispose the machine at a distance from said source, for example, when the heat is supplied from a nuclear reactor, and when the machine has to be protected from the dangers of the radiation released by the nuclear reactions and the like. It may furthermore be advantageous to use that transfer device for establishing a thermal contact between the heaters of a number of thermodynamic machines or the various heaters of a multi-cylinder thermodynamic engine and one and the same common heat source.
In the above-mentioned cases, practice gives rise to a problem: the interruption of the heat transfer from the heat source to the heater. If, for example, a plurality of heaters of one or more machines communicate through separate heat transfer devices with the same heat source, and if the heat transport to one of said heaters has to be interrupted, for examplem because the machine is stopped or because the power of a multi-cylinder thermodynamic engine is reduced by putting a cylinder out of operation, the heat supply from the heat source to the further machines or cylinders has to be continued. It is then not allowed to arrest the production of heat by the heat source, if this is possible, nor is it allowed to remove the heat source. The latter encounters frequent practical difficulties, particularly when the heat source is a heat accumulator forming an integral part of the heat transfer device.
The heat transfer device usually forms part of the machine, so that interruption of the heat transport by removal of the heat transfer device would require a time-consuming dismounting operation, the more difficult on account of the high heater temperatures, which may exceed 700.degree. C in thermodynamiic engines. FInally also turning away and/or displacing of the heat transfer device in conjunction or not in conjunction with the machine with respect to the heat source are attended by great practical inconveniences.